PerkinElmer CLARUS 600 GC, User Manual

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Using the Active Method
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avoid this, the setup procedure is slightly different than the above procedure. When using
a mass spectrometer, you would not want the initial pressure to be too high, because at
the end of the GC run all parameters are set back to their initial values, and the higher
pressure could cause damage to the vacuum system.
For the Clarus GC/MS the initial value is set to the normal operating pressure (flow or
velocity) and a negative timed event with a high pressure (flow or velocity) will be added
to the method. This causes the pressure (flow or velocity) to increase prior to Ready (for
example, prior to the injection). At injection, the GC method holds this pressure (flow or
velocity) for the time necessary to transfer the sample onto the column. The
experimentally determined pressure (flow or velocity) is then programmed at a controlled
rate down to the initial (or normal) column operating pressure (flow or velocity).
If you are using the autosampler, at the end of the last sample in the sequence, the Clarus
MS will go “Not Ready,” thereby sending a signal to the GC keeping it from coming
Ready. (The External Ready must be connected. See the
Clarus 600/680 GC Installation
Instructions, 09936779 .) This keeps the GC from executing the negative timed event and
holds the pressure at the lower setting.
Setting the Split Flow for Splitless Injection
To make a splitless injection, initially turn Off the appropriate split flow that is associated
with your injector with a timed event. Then with another timed event, turn it On from
0.25 to 2 minutes into the GC run and leave it on. When the GC run is complete, the GC
returns the split flow to its initial setting.
To set up for splitless operation:

From the Injector status screen touch the dialog box for Split flow and use the up
and down arrow or keypad
buttons to enter a split flow in mL/min.